If you think it's too late to order something online for Christmas, think again.

That's because two hot trends redefining e-commerce—mobile apps and same-day delivery—have made it possible for you to order gifts at what's truly the last minute, not just FedEx and UPS's shipping cutoff dates.

Same-day delivery is very limited in scope. Right now, San Francisco and New York are the main markets with delivery services which can get you your shopping in as little as an hour.

So far, startups rule the roost. But eBay has entered the same-day delivery market with eBay Now, and Google and Amazon are rumored to be thinking about similar moves.